Referring to FIG. 1, FIG. 1 discloses a rotary support in the prior art. The rotary support includes a bearing inner race 102 and a bearing outer race 100 that is coaxial with and surrounds the bearing inner race 102. Two spaced-apart groups of rolling elements 104 are disposed between the bearing inner race 102 and the bearing outer race 100, in which the bearing inner race 102 and the bearing outer race 100 can rotate relative to each other through the rolling elements 104.
Specifically, multiple threaded holes 103 arranged at equal intervals are disposed in a lower end of the bearing inner race 102. A central axis of the threaded holes 103 is parallel to a central axis of the bearing inner race 102. The threaded holes 103 are used for fixed connection to a first mounting surface of a rotary structure. Multiple threaded holes 101 arranged at equal intervals are disposed in an upper end of the bearing outer race 100. A central axis of the threaded holes 101 is parallel to a central axis of the bearing outer race 100. The threaded holes 101 are used for fixed connection to a second mounting surface of the rotary structure. The first mounting surface and the second mounting surface are opposite in position.
Taking, as a boundary, a plane passing through the center of the rotary support and perpendicular to the central axis, the upper end of the bearing outer race 100 is located on one side of the plane, and the lower end of the bearing inner race 102 is located on the other side of the plane. When the rotary support is mounted to the rotary structure, mounting holes in the first mounting surface are aligned, one by one, with the threaded holes 103 of the bearing inner race 102, rods of bolts are screwed and fixed to the threaded holes 103 through the mounting holes of the first mounting surface, and finally, the bearing inner race 102 is fixedly connected to the first mounting surface, which provides the supporting surface for bolt heads; afterwards, mounting holes of the second mounting surface are aligned, one by one, with the threaded holes 101 of the bearing outer race 100, rods of bolts are screwed and fixed to the threaded hole 101 through the mounting holes of the second mounting surface, and finally, the bearing outer race 100 is fixedly connected to the second mounting surface.
With the aforementioned rotary support, bolts need to be fixedly connected to the threaded holes in the bearing inner race and the bearing outer race through the mounting holes in the first mounting surface and the second mounting surface. However, in some special occasions, there is narrow operating space near the mounting holes of the first mounting surface, so it is hard to lead the bolts into the mounting holes, and there is even no operating space to lead the bolts therein. Or, even if the rods are led into the mounting holes and aligned with the threaded holes, there is no space for a wrench for screwing the bolt heads to reach the bolt heads. Therefore, for occasions in which mounting to the threaded holes in the bearing inner race through the mounting holes of the first mounting surface is inconvenient, the first mounting surface cannot be connected to the rotary support in the opposite direction with the existing rotary support.